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South African Journal of Botany 2002, 68: 430–433 Copyright © NISC Pty Ltd Printed in South Africa — All rights reserved SOUTH AFRICAN JOURNAL OF BOTANY ISSN 0254–6299

Growth of enset ( ventricosum) suckers under different horticultural practices

M Diro1, 2, S Gebremariam2, A Zelleke2 and J van Staden*1

1 Research Centre for Growth and Development, School of Botany and Zoology, University of Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa 2 Ethiopian Agricultural Research Organisation, PO Box 2003, Addis Ababa, * Corresponding author, e-mail: [email protected]

Received 11 March 2002, accepted in revised form 17 July 2002

The influence of three propagation practices and three fewer suckers. On the other hand, the halved , types of enset on the production of suckers was when uprooted and replanted immediately after removal investigated. After removal of apical buds, mother of apical buds or not uprooted from their original grow- corms were uprooted and immediately replanted, not ing sites, gave earlier differentiation of buds and pro- uprooted from original positions and uprooted and duced more suckers. The halved corms also gave more transferred to new planting holes three months later. medium to large suckers than whole and quartered Three corm types: whole, halved and quartered corms corms when evaluated across all the propagation meth- were used. Suckers were harvested one year after ods. An increase in the number of vigorous suckers removal of apical buds. After harvest, the suckers were from halved corms is possible because of elimination of sorted into three size groups: undersized, small and the strong apical dominance while leaving reasonable medium to large. The number of suckers produced per portions of the mother corm to sustain initiation, growth plot, from four planting holes, ranged from 40 to 141 and development of suckers. Therefore, halved corms depending on the treatments. Halved and quartered uprooted and immediately replanted or left in situ can mother corms, when transferred to new planting holes be used to produce more suckers with better growth. three months after removal of apical buds, produced

Introduction

Enset ( (Welw.) Cheesman) is a diploid source of food (Spring 1996). Enset is a productive crop, a (2n = 18) herbaceous perennial morphologically resembling source of income, a cultural medicine and feed for livestock. . The genera Ensete and belong to the The plant is tolerant to transient drought once established. . Enset is the vernacular name used in the Processed products can be stored for a long time without Amharic language in Ethiopia for E. ventricosum. Centres of spoiling thus ensuring stable food supply. Fibre, a by-prod- origin of Ensete are the lowland and mountain areas of uct when enset is processed, is used in local fibre factories Uganda, Tanzania and the Sudan (Smeds 1955) and and partially substitutes for fibre importation. At the environ- Ethiopia (Kuls cited by Westphal 1975). mental level, enset plantations reduce runoff, improve nutri- Horaninow (1862) was the first to describe the ent recycling and thus contribute to a sustainable agriculture. Ensete creating a single , Ensete edule. Cheesman Wild species of Ensete propagate from . Cultivated (1947) revised the genus Ensete reporting 25 species. enset also produces but only after a long juvenile peri- Baker and Simmonds (1953) identified the synonyms where- od. Seed germination is very low because of seed dorman- as Simmonds (1960) with further work reported only six cy. Moreover, since enset utilises its stored carbohydrate species, Ensete gilletii, E. homblei, E. perrieri and E. ventri- during fruiting and eventually dies, it is harvested before or cosum with an African distribution and E. glaucum and E. shortly after flowering, reducing viable seed production. superbum with an Asian distribution. Therefore, propagation by seed is not common. The plant is Enset (Ensete ventricosum) is widely distributed in Africa. usually multiplied vegetatively and grown as clones. Apical It adapted to altitudes between 1 500m and 3 000m in buds are removed from the whole or split corms, after Ethiopia (Bezuneh and Felleke 1966) and is mainly cultivat- uprooting or without uprooting the mother plant (Alemu and ed in the southern and southwestern parts of the country. Sandford 1991, Diro and Tabogie 1994), to initiate sucker- Here it plays a significant economic and social role. About 15 ing. During transplanting, enset growers sort the suckers million people in Ethiopia are dependent on enset as a into size groups. Undersized suckers are replanted in the South African Journal of Botany 2002, 68: 430–433 431 nursery and maintained for extended periods before being Research Centre. The mother were transplanted to ready for transplanting. Replanting the undersized suckers the experimental field a year before application of the treat- in the nursery lengthens the time to maturity and curtails pro- ments. Corms were cut so that they each had a 10cm to duction. Therefore, growers need more vigorous suckers of 15cm pseudostem. The cut surfaces of the corms were enset for cultivation. In banana cultivation, lateral shoots are exposed to sunlight for 48h before covering them with soil. referred to collectively as suckers and those that bear nar- After emergence, plants were regularly weeded. row sword leaves and are attached to the mother rhizome are called sword suckers, which are preferred for planting Data collection since they produce fruit more quickly than smaller ones or pieces of corm (Simmonds 1966, Stover and Simmonds Data collection commenced three months after removal of 1987). Moreover, small and weak suckers are less produc- the apical buds (RAB) and continued during the course of tive (Perez 1991). The use of vigorous suckers is important growth at monthly intervals until the 12th month. Final data to ensure success in establishment and subsequent per- collection was performed after suckers were harvested a formance of enset leading to early and higher yields. Gowen year after removal of the apical buds. The final data were (1995) reported that it is possible to produce more suckers used to evaluate the effects of treatments on sucker produc- of plantains by altering the techniques of traditional propa- tion. Suckers were categorised in three size groups: namely gation. Belhu et al. (1994) reported that more enset suckers undersized, small and medium to large. Categorisation of could be produced from halved corms. Usually, however, the suckers was based on the cultivation practices of farm- suckers are not evaluated in terms of their size and infor- ers around the Centre. Undersized suckers are those that mation is lacking on the effect of corm type under different are replanted in a nursery for onward growth in a group of methods of propagation. Therefore, vegetative enset propa- about three or left attached to the mother corm. Small suck- gation was investigated. This paper reports the growth of ers are those that can be planted directly into the field when- suckers, in number over time, and the influence of method ever there is a shortage of bigger ones. Usually they need of propagation and corm type on sucker production. further growth before placing them in field plantations. Medium to large suckers are those that can be planted Materials and Methods directly into the field. For the measurements of vegetative growth of suckers, Study area pseudostem diameter and sucker heights were recorded for 20 suckers every month. For the final measurements 10 The study was conducted at Areka Agricultural Research suckers per plot from each size group were randomly sam- Centre, southern Ethiopia. The Centre is situated at latitude pled. The data collected were subjected to statistical analy- 7°04’N, longitude 37°41’E and at an altitude of 1 800m with sis using the MSTATC, computer software developed in 1 564mm (eight year average) mean annual rainfall and 1991 by Michigan State University. Duncan’s Multiple Range 64% (three year average) relative humidity. The soil at the Test (DMRT) at a 5% probability level was used to separate site is a silt loam with a pH of 4.5 to 4.9 in the top 30cm of significant means. soil. Results and Discussion Treatments and experimental design Growth of suckers The experiment was designed to examine the effects of three vegetative propagation methods and three corm types More suckers emerged from halved corms three months on sucker growth. The three propagation methods were: after removal of apical buds when mother corms were parent corm uprooted, apical bud removed and corm uprooted and replanted immediately or not uprooted from replanted the same day of uprooting (M1); pseudostem of their original positions (Figure 1). The number of suckers in parent corm cut at soil level, apical bud removed, the corm these treatments reached a maximum five months after covered with soil and left at the same place for a year (M2); removal of apical buds, two months earlier than many of the and pseudostem of the parent corm cut at soil level, apical treatment combinations. Relatively fewer suckers emerged bud removed, the corm covered with soil and transferred to at this time from the whole corms under all propagation a new planting hole after three months (M3). The three corm methods. This increased slowly for seven months after types were the whole corm (C1); halved corms (C2); and removal of apical buds. Many of the late emerged suckers quartered corms (C3). The experiment was laid out as a from the whole corms survived until final harvest of suckers. randomised complete block design with four replications. This appeared to be due to less competition and larger The factorial combinations of three propagation methods reserves in the whole corms. Lower numbers of suckers and three corm types were randomly assigned to each plot were recorded over time from quartered corms with all prop- in the blocks. Experimental plants were protected by guard agation methods. rows. Spacing of 1.5m between planting holes, rows and The general trend of growth with respect to sucker num- blocks were used with a net plot size of 9.0m2 (four planting ber was similar for all treatments, increasing first, reaching a holes). peak and then declining. The decline could partially be attrib- Three-year-old plants, of an enset clone locally known by uted to competition amongst the suckers and moisture a vernacular Halla, were used as mother plants. Halla is the stress during the growing season, causing drying of some popular clone grown in the area around Areka Agricultural suckers. It appears therefore that it is possible to produce 432 Diro, Gebremariam, Zelleke and Van Staden

M1 M2 M3 40 a 35 140 M1C1 ab p< 0.05 30 M1C2 120 abc M1C3 bcd M2C1 100 bcd 25 cde M2C2 80 20 M2C3 def M3C1 60 ef 15 M3C2 ef f M3C3 40 10 NUMBER OF SUCKERS PER HOLE SUCKERS/PLOT 20 5 NUMBER OF TOTAL C1 C2 C3 3456789101112 MONTHS AFTER REMOVAL OF APICAL BUDS CORM TYPE

Figure 1: Number of enset suckers produced over one year with Figure 2: Number of total suckers as affected by interaction different treatments: M1 = replanting mother corms immediately between propagation method and corm type (Bars labelled by the after removal of apical buds; M2 = mother corms not uprooted after same letter are not significantly different from each other at a 5% removal of apical buds; M3 = mother corms transferred to new level of probability). M1 = replanting mother corms immediately holes three months after removal of apical buds; C1 = whole corm; after removal of apical buds; M2 = mother corms not uprooted after C2 = halved corm; C3 = quartered corm removal of apical buds; M3 = mother corms transferred to new holes three months after removal of apical buds; C1 = whole corm; C2 = halved corm; C3 = quartered corm more suckers with supplementary watering and fertilisation in general and especially from halved corms. The effects of propagation methods and corm types on Table 1: Production of different size group of suckers by enset with sucker production were statistically assessed after sucker different propagation method and corm type harvesting (Figure 2). Percent of suckers in each size group, medium to large, small and undersized suckers, is given in Treatment Total suckers produced % Suckers per size group Table 1. There was significant interaction between the ML SS US method of propagation and corm type on the total number of M1 C1 79.50 33.65 30.19 36.16 suckers. Halved corms produced a larger number of final C2 110.25 25.62 32.20 42.18 suckers, when planted immediately after removal of apical C3 64.00 33.59 33.59 32.81 buds or when left undisturbed, than many of the treatment M2 C1 113.75 21.10 21.32 57.58 combinations. Fewer suckers were produced from halved C2 141.50 28.10 28.80 43.11 and quartered corms than from whole ones when mother C3 89.25 28.57 22.97 48.46 corms were transferred to new planting holes three months M3 C1 94.25 21.48 26.26 52.26 C2 52.50 34.76 22.38 42.86 after removal of apical buds. Lower sucker number in these C3 40.00 30.00 21.25 48.75 treatments could be due to damage to suckers when corms were split. ML = medium to large; SS = small suckers; US = undersized suckers Uprooting the whole mother corms and replanting them reduced sucker production compared to those not uprooted. It is thus possible to increase the number of suckers by removing the apical buds but leaving the mother corms that prevent the development of the lateral buds. In in vitro undisturbed. propagation, the first organogenetic formed could No significant interaction between propagation method inhibit the development of further structures of the same kind and corm type was observed with respect to the number of where the inhibitory effect increases, as the pre-formed medium to large suckers, however, significant main effects organs become larger (George and Sherrington 1984). were observed (Table 2). Fewer vigorous, medium to large The highest corm fresh weight per sucker for all factor suckers were obtained when corms were transferred to new combinations was recorded with whole mother corms when planting holes three months after removal of apical buds replanting was done immediately after apical bud removal than with the other two methods. Halved corms gave more (Figure 3). Lower sucker production appeared to favour medium to large suckers than whole and quartered corms. corm growth. Average fresh weight per sucker was influ- Average pseudostem heights were 20cm or less for under- enced by corm type (Table 3). Whole mother corms pro- sized, 21cm to 30cm for small and 31cm or more for medi- duced suckers with a greater fresh weight than quartered um to large suckers in this experiment. corms. The halved corms that produced more medium to The lower number of vigorous suckers from the whole large suckers had a smaller corm fresh weight per sucker. corms could be partially due to some suckers, which This shows that the average corm fresh weight per sucker emerged earlier from the whole corms, taking over apical did not represent growth of all suckers in the group. Heights dominance over the late emerging buds. According to of the pseudostem and the sucker were significantly affect- Edmond et al. (1977), when an apical bud is removed, the ed by the propagation method (Table 3) while the interaction lateral buds just below a cut surface develop rapidly, and and corm type were not affected. Transferring the mother they, in turn, manufacture the growth inhibiting hormones corms three months after removal of apical buds, after suck- South African Journal of Botany 2002, 68: 430–433 433

Table 2: Effect of propagation method and corm type on the mean Table 3: Mean pseudostem height, plant height and fresh weight number of medium to large and undersized enset suckers produced per sucker of enset as affected by propagation method and corm per plot type used

Method or corm type Medium to large Undersized Propagation method Corm type Method Corm type Method Corm type Method or corm type PsH (cm) PlH (cm) SFW (g) 1 25.50 a *23.67 b 32.08 b 47.83 a 1 26.52 a *120.02 a 945.93 a 2 29.75 a 28.75 a 56.58 a 43.33 a 2 24.72 a 112.94 a 841.86 ab 3 16.83 b 19.67 b 30.42 b 27.92 b 3 22.22 b 99.00 b 756.46 b

* Values within the same column followed by a common letter are not * Values in the same column followed by a common letter are not significantly different from each other at a 5% level of probability significantly different from each other at a 5% probability level. PsH = pseudostem height; PlH = plant height; SFW = sucker fresh weight

M1 M2 M3 References a p< 0.05 100 Alemu K, Sandford S (1991) Enset in North Omo Region. Farmers’ b Research Project Technical Pamphlet No. 1, Addis Ababa 80 bc bc Baker RED, Simmonds NW (1953) The genus Ensete in Africa. Kew bc c bc 60 c c Bulletin 8: 405–416 Belhu T, Legesse G, Tabogie E, Diro M (1994) Sweet potato and 40

(g/sucker) enset propagation studies. In: Hearath E, Lemma D (eds) 20 Proceedings of the Second National Horticultural Workshop of Ethiopia. 1–3 December 1992, IAR, Addis Ababa, pp 288–300

CORM FRESH WEIGHT C1 C2 C3 Bezuneh T, Felleke A (1966) The production and utilization of genus CORM TYPE Ensete in Ethiopia. Economic Botany 20: 65–70 Cheesman EE (1947) Classification of the I. The genus Ensete Horan. 2: 97–106 Figure 3: Corm fresh weight of suckers as influenced by propaga- Diro M, Tabogie E (1994) Preliminary investigation on Ensete cul- tion method and corm type (bars labelled by the same letter are not ture. In: Hearath E, Lemma D (eds) Proceedings of the Second significantly different from each other at a 5% level of probability). National Horticultural Workshop of Ethiopia. 1–3 December 1992, M1 = replanting mother corms immediately after removal of apical IAR, Addis Ababa, pp 120–134 buds; M2 = mother corms not uprooted after removal of apical buds; Edmond JB, Senn TL, Andrews FS, Halfacre RG (1977) M3 = mother corms transferred to new holes three months after Fundamentals of Horticulture. Tata McGraw-Hill, Inc., New Delhi removal of apical buds; C1 = whole corm; C2 = halved corm; C3 = George EF, Sherrington PD (1984) Plant Propagation by Tissue quartered corm Culture. Exegetics Ltd, Basingstoke Gowen S (ed) (1995) Bananas and Plantains. Chapman and Hall, London er emergence, reduced heights of suckers. This could be Horaninow P (1862) Prodromus Monographiae Scitaminarum. because of transplant shock. Petropoli Splitting the whole corm longitudinally through an apex Lock JM (1993) Musaceae. In: Polhill RM (ed) Flora of Tropical East into two parts and planting each in a different hole produced Africa. AA Balkema, Rotterdam more than twice the number of suckers than when the Perez L (1991) Comparison of different banana propagation meth- whole corm was planted. Therefore this propagation prac- ods with regard to certain production and growth variables in Grand Naib (Musa AAA) during the first five harvest cycles. tice can be used in the enset growing areas. However, Musarama 4: 4 investigation of the vegetative propagation practices under Simmonds NW (1960) Notes on banana . Kew Bulletin different moisture regimes and management practices may 14: 198–212 generate valuable additional information. Size group espe- Simmonds NW (1966) Bananas. Longman, New York cially proportion of undersized suckers should be taken into Smeds H (1955) The Ensete planting culture of eastern Sidamo, consideration when one evaluates sucker production under Ethiopia. Acta Geographia Helsingfors 13: 40 different treatments. It is also important to study the influ- Spring A (1996) Enset farming system in Southern Region, Ethiopia. ence of size of suckers on establishment, growth and final Report on a rapid rural appraisal in Gurage, Hadiya and Sidama yield of enset. Zones. Enset Needs Assessment Project Phase I, Awasa, Ethiopia rd Acknowledgements — We thank Areka Agricultural Research Stover RH, Simmonds NW (1987) Bananas. 3 ed, John Wiley and Centre and The Ethiopian Agricultural Research Organisation (for- Sons Inc., New York merly the Institute of Agricultural Research) for providing the facili- Westphal E (1975) Agricultural Systems in Ethiopia. Centre for ties to conduct this study. Agricultural Publishing and Documentation, Wageningen

Edited by NAC Brown